RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033   6 KHLVKDFNPYITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETNPLEMLRLDNTLEEIIFKLVPG 85
Cdd:cd16737    1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                         90
                 ....*....|....*
gi 380036033  86 LREQELERESEFWKK 100
Cdd:cd16737   81 LRERELQREAEFWEK 95

RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033   6 KHLVKDFNPYITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETNPLEMLRLDNTLEEIIFKLVPG 85
Cdd:cd16737    1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                         90
                 ....*....|....*
gi 380036033  86 LREQELERESEFWKK 100
Cdd:cd16737   81 LRERELQREAEFWEK 95

Zinc finger, C3HC4 type (RING finger);

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 380036033   18 CYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:pfam13923   2 CPICMDMLKDPSTTTPCGHVFCQDCILRALRAGNECPLC 40

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 380036033    18 CYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSND-CPRC 56
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLESGNNtCPIC 40

RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033   6 KHLVKDFNPYITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETNPLEMLRLDNTLEEIIFKLVPG 85
Cdd:cd16737    1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                         90
                 ....*....|....*
gi 380036033  86 LREQELERESEFWKK 100
Cdd:cd16737   81 LRERELQREAEFWEK 95

RRING finger- and WD40-associated ubiquitin-like (RAWUL) domain found in PCGF1-6, RING1 and -2, DRIP and similar proteins; structurally similar to a beta-grasp ubiquitin-like fold; The family includes six Polycomb Group (PcG) RING finger homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) that use epigenetic mechanisms to maintain or repress expression of their target genes. They were first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place, and are well known for silencing Hox genes through modulation of chromatin structure during embryonic development in fruit flies. PCGF homologs play important roles in cell proliferation, differentiation, and tumorigenesis. They all have been found to associate with ring finger protein 2 (RNF2). The RNF2-PCGF heterodimer is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. Moreover, PCGF homologs are critical components in the assembly of distinct Polycomb Repression Complex 1 (PRC1) related complexes which are involved in the maintenance of gene repression and target different genes through distinct mechanisms. The Drosophila PRC1 core complex is formed by the Polycomb (Pc), Polyhomeotic (Ph), Posterior sex combs (Psc), and Sex combs extra (Sce, also known as Ring) subunits. In mammals, the composition of PRC1 is much more diverse and varies depending on the cellular context. All PRC1 complexes contain homologs of the Drosophila Ring protein. Ring1A/RNF1 and Ring1B/RNF2 are E3 ubiquitin ligases that mark lysine 119 of histone H2A with a single ubiquitin group (H2AK119ub). Mammalian homologs of the Drosophila Psc protein, such as PCGF2/Mel-18 or PCGF4/BMI1, regulate PRC1 enzymatic activity. PRC1 complexes can be divided into at least two classes according to the presence or absence of CBX proteins, which are homologs of Drosophila Pc. Canonical PRC1 complexes contain CBX proteins that recognize and bind H3K27me3, the mark deposited by PRC2. Therefore, canonical PRC1 complexes and PRC2 can act together to repress gene transcription and maintain this repression through cell division. Non-canonical PRC1 complexes, containing RYBP (together with additional proteins, such as L3mbtl2 or Kdm2b) rather than the CBX proteins, have recently been described in mammals. PCGF homologs contain a C3HC4-type RING-HC finger, and a RAWUL domain that might be responsible for interaction with Cbx members of the Polycomb repression complexes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033 138 QIAICLDCLRNNGqsgDNVVKGLMKKFIRCSTRVTVGTIKKFLSLKLKLPSSYELDVLCNGEIMGKDHTMEFIYMTRWRL 217
Cdd:cd16102    1 QVSLSLEPSESNL---GGKLPQLEKPYLRCSARATVGHLKKFLRRKLKLDSEQDLDILCRGELLGKEHTLKFIWRTRWRK 77

                         90       100       110
                 ....*....|....*....|....*....|...
gi 380036033 218 rgenfrclncsasqvcsqdgplyQSYPMVLQYR 250
Cdd:cd16102   78 -----------------------QDGPLVLQYR 87

RING finger found in polycomb group RING finger protein 2 (PCGF2) and similar proteins; PCGF2, also known as DNA-binding protein Mel-18, RING finger protein 110 (RNF110), or zinc finger protein 144 (ZNF144), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR). It serves as the core component of a canonical Polycomb repressive complex 1 (PRC1), which is composed of a chromodomain-containing protein (CBX2, CBX4, CBX6, CBX7 or CBX8) and a Polyhomeotic protein (PHC1, PHC2, or PHC3). Like other PCGF homologs, PCGF2 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. Moreover, PCGF2 uniquely regulates PRC1 to specify mesoderm cell fate in embryonic stem cells. It is required for PRC1 stability and maintenance of gene repression in embryonic stem cells (ESCs) and essential for ESC differentiation into early cardiac-mesoderm precursors. PCGF2 also plays a significant role in the angiogenic function of endothelial cells (ECs) by regulating endothelial gene expression. Furthermore, PCGF2 is a SUMO-dependent regulator of hormone receptors. It facilitates the deSUMOylation process by inhibiting PCGF4/BMI1-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). It is also a novel negative regulator of breast cancer stem cells (CSCs) that inhibits the stem cell population and in vitro and in vivo self-renewal through the inactivation of Wnt-mediated Notch signaling. PCGF2 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 380036033   9 VKDFNPYITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETNPLEMLRLDNTLEEIIFK 81
Cdd:cd16734    8 ITELNPHLMCALCGGYFIDAATIVECLHSFCKTCIVRYLETNKYCPMCDVQVHKTRPLLSIRSDKTLQDIVYK 80

RING finger found in polycomb group RING finger protein 3 (PCGF3) and similar proteins; PCGF3, also known as RING finger protein 3A (RNF3A), is one of six PcG RING finger (PCGF) homologs (PCGF1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF3 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF3 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 380036033   5 RKHLVKDFNPYITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETNPLEMLR 70
Cdd:cd16735    1 RKIRLKDLNAHITCRLCKGYLIDATTITECLHTFCKSCLVKYLEENNTCPTCGIVIHQSHPLQYIG 66

RING finger- and WD40-associated ubiquitin-like (RAWUL) domain found in polycomb group RING finger protein 3 (PCGF3) and similar proteins; PCGF3, also termed RING finger protein 3A (RNF3A), is one of six PcG RING finger (PCGF) homologs (PCGF1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF3 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF3 contains a C3HC4-type RING-HC finger, and a RAWUL domain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033 138 QIAICLDCLRNNgqsgdnvVKGLMKKFIRCSTRVTVGTIKK--FLSLKLKLPSSYELDVLCNGEIMGKDHTMEFIYMTRW 215
Cdd:cd17083    1 QVNICLECNSNN-------LKPLKRKYIRCSSQATITHLKKfiAKKLFLDIFRYNEVDILCNEEILGKDHTLKFVTVTRW 73

                 ...
gi 380036033 216 RLR 218
Cdd:cd17083   74 RFK 76

RAWUL domain RING finger- and WD40-associated ubiquitin-like; The RAWUL domain is found at the C-terminus of poly-comb group RING finger proteins. It is a ubiquitin-like domain. RAWUL binds directly to PUFD, a domain on BCOR proteins (BCL6 corepressor). BCOR has emerged as an important player in development and health.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033  163 KFIRCSTRVTVGTIKKFLSLKLKLP--SSYELDVLCNGEIMGKDHTMEFIYMTRWRLRGenfrclncsasqvcsqdgply 240
Cdd:pfam16207   1 RYLKCPANATVDHLKKYLAMKLGLElqNEYIVEILYNGEPLPDSYTLDVAYIKYWKRNA--------------------- 59

                          90
                  ....*....|
gi 380036033  241 qsyPMVLQYR 250
Cdd:pfam16207  60 ---PLELYYR 66

Zinc finger, C3HC4 type (RING finger);

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 380036033   18 CYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:pfam13923   2 CPICMDMLKDPSTTTPCGHVFCQDCILRALRAGNECPLC 40

RING finger, HC subclass, found in really interesting new gene proteins RING1, RING2 and similar proteins; RING1, also known as polycomb complex protein RING1, RING finger protein 1 (RNF1), or RING finger protein 1A (RING1A), is a transcriptional repressor that is associated with the Polycomb group (PcG) protein complex involved in stable repression of gene activity. RING2, also known as huntingtin-interacting protein 2-interacting protein 3, HIP2-interacting protein 3, protein DinG, RING finger protein 1B (RING1B), RING finger protein 2 (RNF2), or RING finger protein BAP-1, is an E3 ubiquitin-protein ligase that interacts with both nucleosomal DNA and an acidic patch on histone H4 to achieve the specific monoubiquitination of K119 on histone H2A (H2AK119ub), thereby playing a central role in histone code and gene regulation. Both RING1 and RING2 are core components of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. RING2 acts as the main E3 ubiquitin ligase on histone H2A of the PRC1 complex, while RING1 may rather act as a modulator of RNF2/RING2 activity. Members of this family contain a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 380036033  16 ITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSN-DCPRC 56
Cdd:cd16531    2 LMCPICLGIIKNTMTVKECLHRFCAECIEKALRLGNkECPTC 43

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 380036033    18 CYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSND-CPRC 56
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLESGNNtCPIC 40

RING finger, HC subclass, found in RING finger proteins RNF113A, RNF113B, and similar proteins; RNF113A, also known as zinc finger protein 183 (ZNF183), is an E3 ubiquitin-protein ligase that physically interacts with the E2 protein, UBE2U. A nonsense mutation in RNF113A is associated with an X-linked trichothiodystrophy (TTD). Its yeast ortholog Cwc24p is predicted to have a spliceosome function and acts in a complex with Cef1p to participate in pre-U3 snoRNA splicing, indirectly affecting pre-rRNA processing. It is also important for the U2 snRNP binding to primary transcripts and co-migrates with spliceosomes. Moreover, the ortholog of RNF113A in fruit flies may also act as a spliceosome and is hypothesized to be involved in splicing, namely within the central nervous system. The ortholog in Caenorhabditis elegans is involved in DNA repair of inter-strand crosslinks. RNF113B, also known as zinc finger protein 183-like 1, shows high sequence similarity with RNF113A. Both RNF113A and RNF113B contain a CCCH-type zinc finger, which is commonly found in RNA-binding proteins involved in splicing, and a C3HC4-type RING-HC finger, which is frequently found in E3 ubiquitin ligases.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 380036033  17 TCYICKGYLIKPTtVTECLHTFCKTCIVQHFEDSNDCPRCGNQ 59
Cdd:cd16539    7 ACFICRKPFKNPV-VTKCGHYFCEKCALKHYRKSKKCFVCGKQ 48

RING-finger-containing E3 ubiquitin ligase [Signal transduction mechanisms];

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 380036033  18 CYICKGYLIKPTtVTECLHTFCKTCIVQHFEDSNDCPRCGNQVHETnpleMLRLDNTLEEII 79
Cdd:COG5432   28 CRICDCRISIPC-ETTCGHTFCSLCIRRHLGTQPFCPVCREDPCES----RLRGSSGSREIN 84

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Deltex3 (DTX3), Deltex-3-like (DTX3L) and similar proteins; This subfamily contains Deltex3 (DTX3) and Deltex-3-like (DTX3L), both of which are E3 ubiquitin-protein ligases belonging to the Deltex (DTX) family. DTX3, also known as RING finger protein 154 (RNF154), has a biological function that remains unclear. DTX3L, also known as B-lymphoma- and BAL-associated protein (BBAP) or Rhysin-2 (Rhysin2), regulates endosomal sorting of the G protein-coupled receptor CXCR4 from endosomes to lysosomes. It also regulates subcellular localization of its partner protein, B aggressive lymphoma (BAL), by a dynamic nucleocytoplasmic trafficking mechanism. In contrast to other DTXs, both DTX3 and DTX3L contain a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain. DTX3L can associate with DTX1 through its unique N termini and further enhance self-ubiquitination.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 380036033  17 TCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRCG 57
Cdd:cd16506    2 TCPICLDEIQNKKTLEKCKHSFCEDCIDRALQVKPVCPVCG 42

RING finger, HC subclass, found in really interesting new gene 1 protein (RING1) and similar proteins; RING1, also known as polycomb complex protein RING1, RING finger protein 1 (RNF1), or RING finger protein 1A (RING1A), was identified as a transcriptional repressor that is associated with the Polycomb group (PcG) protein complex involved in stable repression of gene activity. It is a core component of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase that transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. RING1 interacts with multiple PcG proteins and displays tumorigenic activity. It also shows zinc-dependent DNA binding activity. Moreover, RING1 inhibits transactivation of the DNA-binding protein recombination signal binding protein-Jkappa (RBP-J) by Notch through interaction with the LIM domains of KyoT2. RING1 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 380036033  16 ITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSN-DCPRCGNQVHETNPlemLRLDNTLEEIIFKLVP 84
Cdd:cd16739    4 LMCPICLDMLKNTMTTKECLHRFCSDCIVTALRSGNkECPTCRKKLVSKRS---LRPDPNFDALISKIYP 70

RING finger- and WD40-associated ubiquitin-like (RAWUL) domain found in polycomb group RING finger protein 6 (PCGF6) and similar proteins; PCGF6, also termed Mel18 and Bmi1-like RING finger (MBLR), or RING finger protein 134 (RNF134), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5 and PCGF6/MBLR), and serves as the core component of a noncanonical Polycomb repressive complex 1 (PRC1)-like L3MBTL2 complex, which is composed of some canonical components, such as RNF2, CBX3, CXB4, CXB6, CXB7 and CXB8, as well as some noncanonical components, such as L3MBTL2, E2F6, WDR5, HDAC1 and RYBP, and plays critical roles in epigenetic transcriptional silencing in higher eukaryotes. Like other PCGF homologs, PCGF6 possesses the transcriptional repression activity, and also associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. Moreover, PCGF6 can regulate the enzymatic activity of JARID1d/KDM5D, a trimethyl H3K4 demethylase, through the direct interaction with it. Furthermore, PCGF6 is expressed predominantly in meiotic and post-meiotic male germ cells and may play important roles in mammalian male germ cell development. It also regulates mesodermal lineage differentiation in mammalian embryonic stem cells (ESCs) and functions in induced pluripotent stem (iPS) reprogramming. The activity of PCGF6 is found to be regulated by cell cycle dependent phosphorylation. PCGF6 contains a C3HC4-type RING-HC finger, and a RAWUL domain.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 380036033 138 QIAICLDCLRNNGQSGDnvVKGLMKKFIRCSTRVTVGTIKKFLSLKLKLPSSYELDVLCNGEIMGKDHTMEFIY 211
Cdd:cd17085    1 DVSLLLEFIGAQEGSDN--FKPLEKKYIRVSGEATVGHVEKFLRKKLNLDSTCEVDILCGEHILENYQTLREIR 72

HC subclass of RING (RING-HC) finger and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle, and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 380036033  17 TCYICKGYLIKPTtVTECLHTFCKTCIVQHFEDSN-DCPRC 56
Cdd:cd16449    2 ECPICLERLKDPV-LLPCGHVFCRECIRRLLESGSiKCPIC 41

RING finger, HC subclass, found in RING finger protein 8 (RNF8) and similar proteins; RNF8 is a telomere-associated E3 ubiquitin-protein ligase that plays an important role in DNA double-strand break (DSB) repair via histone ubiquitination. It is localized in the nucleus and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3), but not with other E2s (UbcH5, UbcH7, UbcH10, hCdc34, and hBendless). It recruits UBC13 for lysine 63-based self polyubiquitylation. Its deficiency causes neuronal pathology and cognitive decline, and its loss results in neuron degeneration. RNF8, together with RNF168, catalyzes a series of ubiquitylation events on substrates such as H2A and H2AX, with the H2AK13/15 ubiquitylation being particularly important for recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of DSBs. RNF8 mediates the ubiquitination of gammaH2AX, and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DNA damage response (DDR) and inhibits chromosomal instability. Moreover, RNF8 interacts with retinoid X receptor alpha (RXR alpha) and enhances its transcription-stimulating activity. It also regulates the rate of exit from mitosis and cytokinesis. RNF8 contains an N-terminal forkhead-associated (FHA) domain and a C-terminal C3HC4-type RING-HC finger.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 380036033  18 CYICKGYLIKPTTVTeCLHTFCKTCIVQHFEDSNDCPRCGNQVheTNPLEMLRLDNTLEEII 79
Cdd:cd16535    4 CSICSELFIEAVTLN-CSHSFCSYCITEWMKRKKECPICRKPI--TSKTRSLVLDNCIDKMV 62

RING finger, HC subclass, found in tripartite motif-containing protein 39 (TRIM39) and similar proteins; TRIM39, also known as RING finger protein 23 (RNF23) or testis-abundant finger protein, is an E3 ubiquitin-protein ligase that plays a role in controlling DNA damage-induced apoptosis through inhibition of the anaphase promoting complex (APC/C), a multiprotein ubiquitin ligase that controls multiple cell cycle regulators, including cyclins, geminin, and others. TRIM39 also functions as a regulator of several key processes in the proliferative cycle. It directly regulates p53 stability. It modulates cell cycle progression and DNA damage responses via stabilizing p21. Moreover, TRIM39 negatively regulates the nuclear factor kappaB (NFkappaB)-mediated signaling pathway through stabilization of Cactin, an inhibitor of NFkappaB- and Toll-like receptor (TLR)-mediated transcription, which is induced by inflammatory stimulants such as tumor necrosis factor alpha. Furthermore, TRIM39 is a MOAP-1-binding protein that can promote apoptosis signaling through stabilization of MOAP-1 via the inhibition of its poly-ubiquitination process. TRIM39 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 380036033  15 YITCYICKGYLIKPTTVtECLHTFCKTCIVQHFEDSND---CPRC 56
Cdd:cd16601    1 EASCSLCKEYLKDPVII-ECGHNFCRACITRFWEELDGdfpCPQC 44

RING finger, HC subclass, found in postreplication repair protein RAD18 and similar proteins; RAD18, also known as HR18 or RING finger protein 73 (RNF73), is an E3 ubiquitin-protein ligase involved in post replication repair of UV-damaged DNA via its recruitment to stalled replication forks. It associates to the E2 ubiquitin conjugating enzyme UBE2B to form the UBE2B-RAD18 ubiquitin ligase complex involved in mono-ubiquitination of DNA-associated PCNA on K164. It also interacts with another E2 ubiquitin conjugating enzyme RAD6 to form a complex that monoubiquitinates proliferating cell nuclear antigen at stalled replication forks in DNA translesion synthesis. Moreover, Rad18 is a key factor in double-strand break DNA damage response (DDR) pathways via its association with K63-linked polyubiquitylated chromatin proteins. It can function as a mediator for DNA damage response signals to activate the G2/M checkpoint in order to maintain genome integrity and cell survival after ionizing radiation (IR) exposure. RAD18 contains a C3HC4-type RING-HC finger, a ubiquitin-binding zinc finger domain (UBZ), a SAP (SAF-A/B, Acinus and PIAS) domain, and a RAD6-binding domain (R6BD).

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 380036033  18 CYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:cd16529    7 CPICFEYFNTAMMITQCSHNYCSLCIRRFLSYKTQCPTC 45

Uncharacterized conserved protein, contains RING and CCCH-type Zn-fingers [General function prediction only];

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 380036033  18 CYICKGYLIKPTtVTECLHTFCKTCIVQHFEDSNDCPRCGNQVH 61
Cdd:COG5152  199 CGICKKDYESPV-VTECGHSFCSLCAIRKYQKGDECGVCGKATY 241

first RING finger, HC subclass, found in the LON peptidase N-terminal domain and RING finger protein family; The LON peptidase N-terminal domain and RING finger protein family includes LONRF1 (also known as RING finger protein 191 or RNF191), LONRF2 (also known as RING finger protein 192, RNF192, or neuroblastoma apoptosis-related protease), LONRF3 (also known as RING finger protein 127 or RNF127), which are characterized by containing two C3HC4-type RING-HC fingers, four tetratricopeptide (TPR) repeats, and an ATP-dependent protease La (LON) substrate-binding domain at the C-terminus. Their biological functions remain unclear. This model corresponds to the first RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 380036033  15 YITCYICKGYLIKPTTVTeCLHTFCKTCIvqHFEDSNDCPRCGNQVH 61
Cdd:cd16513    2 LLSCPLCRGLLFEPVTLP-CGHTFCKRCL--ERDPSSRCRLCRLKLS 45

RING finger, HC subclass, found in tripartite motif-containing protein 62 (TRIM62) and similar proteins; TRIM62, also known as Ductal Epithelium Associated Ring Chromosome 1 (DEAR1), is a cytoplasmic E3 ubiquitin-protein ligase that was identified as a dominant regulator of acinar morphogenesis in the mammary gland. It is implicated in the inflammatory response of immune cells by regulating the Toll-like receptor 4 (TLR4) signaling pathway, leading to increased activity of the activator protein 1 (AP-1) transcription factor in primary macrophages. It is also involved in muscular protein homeostasis, especially during inflammation-induced atrophy, and may play a role in the pathogenesis of ICU-acquired weakness (ICUAW) by activating and maintaining inflammation in myocytes. Moreover, TRIM62 facilitates K27-linked poly-ubiquitination of CARD9 and also regulates CARD9-mediated anti-fungal immunity and intestinal inflammation. It also functions as a chromosome 1p35 tumor suppressor and negatively regulates transforming growth factor beta (TGFbeta)-driven epithelial-mesenchymal transition (EMT) by binding to and promoting the ubiquitination of SMAD3, a major effector of TGFbeta-mediated EMT. TRIM62 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 380036033  16 ITCYICKGYLIKPTTVTeCLHTFCKTCIVQHF--EDSNDCPRC 56
Cdd:cd16608    7 LLCSICLSIYQDPVSLG-CEHYFCRQCITEHWsrSEHRDCPEC 48

RING finger, HC subclass, found in tripartite motif-containing protein TRIM21 and similar proteins; TRIM21, also known as 52 kDa Ro protein, 52 kDa ribonucleoprotein autoantigen Ro/SS-A, Ro(SS-A), RING finger protein 81 (RNF81), or Sjoegren syndrome type A antigen (SS-A), is a ubiquitously expressed E3 ubiquitin-protein ligase and a high affinity antibody receptor uniquely expressed in the cytosol of mammalian cells. As a cytosolic Fc receptor, TRIM21 binds the Fc of virus-associated antibodies and targets the complex in the cytosol for proteasomal degradation in a process known as antibody-dependent intracellular neutralization (ADIN), and provides an intracellular immune response to protect host defense against pathogen infection. It shows remarkably broad isotype specificity as it does not only bind IgG, but also IgM and IgA. Moreover, TRIM21 promotes the cytosolic DNA sensor cGAS and the cytosolic RNA sensor RIG-I sensing of viral genomes during infection by antibody-opsonized virus. It stimulates inflammatory signaling and activates innate transcription factors, such as nuclear factor-kappaB (NF-kappaB). TRIM21 also plays an essential role in p62-regulated redox homeostasis, suggesting it may be a viable target for treating pathological conditions resulting from oxidative damage. Furthermore, TRIM21 may have implications for various autoimmune diseases associated with uncontrolled antiviral signaling through the regulation of Nmi-IFI35 complex-mediated inhibition of innate antiviral response. TRIM21 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 380036033  16 ITCYICKGYLIKPTTvTECLHTFCKTCIVQHFEDSND-CPRCGNQ 59
Cdd:cd16596   10 VTCPICLDPFVEPVS-IECGHSFCQECISQVGKGGGSvCPVCRQR 53

RING finger, HC subclass, found in RING finger protein 213 (RNF213) and similar proteins; RNF213, also known as ALK lymphoma oligomerization partner on chromosome 17 or Moyamoya steno-occlusive disease-associated AAA+ and RING finger protein (mysterin), is an intracellular soluble protein that functions as an E3 ubiquitin-protein ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. It plays a unique role in endothelial cells for proper gene expression in response to inflammatory signals from the environment. Mutations in RNF213 may be associated with Moyamoya disease (MMD), an idiopathic cerebrovascular occlusive disorder prevalent in East Asia. It also acts as a nuclear marker for acanthomorph phylogeny. RNF213 contains two tandem enzymatically active AAA+ ATPase modules and a C3HC4-type RING-HC finger. It can form a huge ring-shaped oligomeric complex.

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 380036033  18 CYICKGYLIKPTTVtECLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:cd16561    5 CSICLEDLNDPVKL-PCDHVFCEECIRQWLPGQMSCPLC 42

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM60, TRIM61, TRIM75 and similar proteins; TRIM60, also known as RING finger protein 129 (RNF129) or RING finger protein 33 (RNF33), is a cytoplasmic protein expressed in the testis. It may play an important role in the spermatogenesis process, the development of the preimplantation embryo, and in testicular functions. RNF33 interacts with the cytoplasmic kinesin motor proteins KIF3A and KIF3B suggesting possible contribution to cargo movement along the microtubule in the expressed sites. It is also involved in spermatogenesis in Sertoli cells under the regulation of nuclear factor-kappaB (NF-kappaB). TRIM75 mainly localizes within spindles, suggesting it may function in spindle organization and thereby affect meiosis. Both TRIM60 and TRIM75 belong the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B2-box, and two coiled coil domains, as well as a PRY domain and a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. In contrast, TRIM61 belongs to the C-V subclass of the TRIM family that contains RBCC domains only. Its biological function remains unclear.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 380036033  16 ITCYICKGYLIKPTTvTECLHTFCKTCIVQHFEDSND---CPRC 56
Cdd:cd16607    2 ASCPICLDYLKDPVT-INCGHNFCRSCISMSWKDLQDtfpCPVC 44

Modified RING finger, HC subclass (C3HC3D-type), found in neuregulin receptor degradation protein-1 (Nrdp1) and similar proteins; Nrdp1 (referred to as FLRF in mice), also known as RING finger protein 41 (RNF41), is an E3 ubiquitin-protein ligase that plays a critical role in the regulation of cell growth and apoptosis, inflammation and production of reactive oxygen species (ROS), as well as in doxorubicin (DOX)-induced cardiac injury. It promotes the degradation of the epidermal growth factor receptor (EGFR/ErbB) family member, ErbB3, which is independent of growth factor stimulation. It also promotes M2 macrophage polarization by ubiquitinating and activating transcription factor CCAAT/enhancer-binding protein beta (C/EBPbeta) via Lys-63-linked ubiquitination. Moreover, Nrdp1 interacts with and modulates the activity of Parkin, a causative protein for early onset recessive juvenile parkinsonism (AR-JP). It also interacts with ubiquitin-specific protease 8 (USP8), which is involved in trafficking of various transmembrane proteins. Furthermore, Nrdp1 inhibits basal lysosomal degradation and enhances ectodomain shedding of JAK2-associated cytokine receptors. Its phosphorylation by the kinase Par-1b (also known as MARK2) is required for epithelial cell polarity. Nrdp1 contains an N-terminal modified C3HC3D-type RING-HC finger required for enhancing ErbB3 degradation, a B-box, a coiled-coil domain responsible for Nrdp1 oligomerization, and a C-terminal ErbB3-binding domain.

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 380036033  16 ITCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSNDCP 54
Cdd:cd16634    2 LICPICSGVLEEPLQAPHCEHAFCNACITEWLSRQQTCP 40

RING finger, HC subclass, found in tripartite motif-containing protein 26 (TRIM26) and similar proteins; TRIM26, also known as acid finger protein (AFP), RING finger protein 95 (RNF95), or zinc finger protein 173 (ZNF173), is an E3 ubiquitin-protein ligase that negatively regulates interferon-beta production and antiviral response through polyubiquitination and degradation of nuclear transcription factor IRF3. It functions as an important regulator for RNA virus-triggered innate immune response by bridging TBK1 to NEMO (NF-kappaB essential modulator, also known as IKKgamma) and mediating TBK1 activation. It also acts as a novel tumor suppressor of hepatocellular carcinoma by regulating cancer cell proliferation, colony forming ability, migration, and invasion. TRIM26 belongs the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 380036033  16 ITCYICKGYLIKPTTVtECLHTFCKTCIVQHFEDSND-----CPRC 56
Cdd:cd16598    5 VTCSICLDYLRDPVTI-DCGHNFCRSCITDYCPISGGherpvCPLC 49

Variant RING finger, HC subclass (C4C4-type), found in retinoblastoma-binding protein 6 (RBBP6) and similar proteins; RBBP6, also known as proliferation potential-related protein, protein P2P-R, retinoblastoma-binding Q protein 1 (RBQ-1), or p53-associated cellular protein of testis (PACT), is a nuclear E3 ubiquitin-protein ligase involved in multiple processes, such as the control of gene expression, mitosis, cell differentiation, and cell apoptosis. It plays a role in both promoting and inhibiting apoptosis in many human cancers, including esophageal, lung, hepatocellular, and colon cancers, familial myeloproliferative neoplasms, as well as in human immunodeficiency virus-associated nephropathy (HIVAN). It functions as an Rb- and p53-binding protein that plays an important role in chaperone-mediated ubiquitination and possibly in protein quality control. It acts as a scaffold protein to promote the assembly of the p53/TP53-MDM2 complex, resulting in an increase of MDM2-mediated ubiquitination and degradation of p53/TP53, and leading to both apoptosis and cell growth. It is also a double-stranded RNA-binding protein that plays a role in mRNA processing by regulating the human polyadenylation machinery and modulating expression of mRNAs with AU-rich 3' untranslated regions (UTRs). Moreover, RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38 that negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Furthermore, RBBP6 is involved in tunicamycin-induced apoptosis by mediating protein kinase (PKR) activation. RBBP6 contains an N-terminal ubiquitin-like domain and a C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger. RBBP6 interacts with chaperones Hsp70 and Hsp40 through its N-terminal ubiquitin-like domain. It promotes the ubiquitination of p53 by Hdm2 in an E4-like manner through its RING finger. It also interacts directly with the pro-proliferative transcription factor Y-box-binding protein-1 (YB-1) via its RING finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 380036033  17 TCYICKGYLIKPTTVTECLHTFCKTCIVQHFEDSND-CPRCGN 58
Cdd:cd16620    5 KCPICKDLMKDAVLTPCCGNSFCDECIRTALLEEDFtCPTCKE 47

RING finger, HC subclass, found in topoisomerase I-binding arginine/serine-rich protein (Topors) and similar proteins; Topors, also known as topoisomerase I-binding RING finger protein, tumor suppressor p53- binding protein 3, or p53-binding protein 3 (p53BP3), is a ubiquitously expressed nuclear E3 ubiquitin-protein ligase that can ligate both ubiquitin and small ubiquitin-like modifier (SUMO) to substrate proteins in the nucleus. It contains an N-terminal C3HC4-type RING-HC finger which ligates ubiquitin to its target proteins including DNA topoisomerase I, p53, NKX3.1, H2AX, and the AAV-2 Rep78/68 proteins. As a RING-dependent E3 ubiquitin ligase, Topors works with the E2 enzymes UbcH5a, UbcH5c, and UbcH6, but not with UbcH7, CDC34, or UbcH2b. Topors acts as a tumor suppressor in various malignancies. It regulates p53 modification, suggesting it may be responsible for astrocyte elevated gene-1 (AEG-1, also known as metadherin, or LYRIC) ubiquitin modification. Plk1-mediated phosphorylation of Topors inhibits Topors-mediated sumoylation of p53, whereas p53 ubiquitination is enhanced, leading to p53 degradation. It also functions as a negative regulator of the prostate tumor suppressor NKX3.1. Moreover, Topors is associated with promyelocytic leukemia nuclear bodies, and may be involved in the cellular response to camptothecin. It also plays a key role in the turnover of H2AX protein, discriminating the type of DNA damaging stress. Furthermore, Topors is a cilia-centrosomal protein associated with autosomal dominant retinal degeneration. Mutations in TOPORS cause autosomal dominant retinitis pigmentosa (adRP).

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                 ....*....|....*....|....*....|....*....|.
gi 380036033  17 TCYICKGYLIKPTTVTE-CLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:cd16574    3 SCPICLDRFENEKAFLDgCFHAFCFTCILEWSKVKNECPLC 43

RING finger, HC subclass, found in RING finger protein 219 (RNF219) and similar proteins; RNF219 may function as a modulator of late-onset Alzheimer's disease (LOAD) associated amyloid beta A4 precursor protein (APP) endocytosis and metabolism. It genetically interacts with apolipoprotein E epsilon4 allele (APOE4). Thus, a genetic variant of RNF219 was found to affect amyloid deposition in human brain and LOAD age-of-onset. Moreover, common genetic variants at the RNF219 locus had been associated with alternations in lipid metabolism, cognitive performance and central nervous system ventricle volume. RNF219 contains a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 380036033  16 ITCYICKGYLIKPTTVTEcLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:cd16562    2 ISCHICLGKVRQPVICSN-NHVFCSSCMDVWLKNNNQCPAC 41

RING finger, HC subclass, found in peroxin-10 (PEX10) and similar proteins; PEX10, also known as peroxisome biogenesis factor 10, peroxisomal biogenesis factor 10, peroxisome assembly protein 10, or RING finger protein 69 (RNF69), is an integral peroxisomal membrane protein with two transmembrane regions and a C3HC4-type RING-HC finger within its cytoplasmically exposed C-terminus. It plays an essential role in peroxisome assembly, import of target substrates, and recycling or degradation of protein complexes and amino acids. It is an essential component of the spinal locomotor circuit, and thus its mutations may be involved in peroxisomal biogenesis disorders (PBD). Mutations in human PEX10 also result in autosomal recessive ataxia. Moreover, PEX10 functions as an E3-ubiquitin ligase with an E2, UBCH5C. It mono- or poly-ubiquitinates PEX5, a key player in peroxisomal matrix protein import, in a UBC4-dependent manner, to control PEX5 receptor recycling or degradation. It also links the E2 ubiquitin conjugating enzyme PEX4 to the protein import machinery of the peroxisome.

                         10        20
                 ....*....|....*....|....*...
gi 380036033  29 TTVTECLHTFCKTCIVQHFEDSNDCPRC 56
Cdd:cd16527   13 PTATPCGHLFCWSCITEWCNEKPECPLC 40